1. Field of the Invention
The invention relates to a polymer composite p-n junction and its method of manufacture and also relates to a polymer composite diode incorporating the polymer with p-n junctions.
2. Description of Related Art
Carbon nanotubes (CNTs), including multiple concentric shells, were first discovered by Iijima in 1991 (Nature, Vol. 354, Nov. 7, 1991, pp. 56-58). Subsequent to this discovery, single-wall carbon nanotubes (SWNTs), including a single graphene layer (i.e., the 2-D equivalent of graphite) rolled up on itself, were synthesized in an arc-discharge process using carbon electrodes doped with transition metals. The carbon nanotubes (especially SWNTs) possess exceptional mechanical, electrical, and thermal properties, and such properties make them attractive for the next generation of composite materials. CNTs are expected to serve as mechanical reinforcements for lightweight composite systems with further promise of multi-functionality. For instance, SWNTs possess a tensile strength of 50-100 GPa and a modulus of 1-2 Tpa—five and ten times greater than steel, respectively, at just one-sixth the weight. CNTs not only have the desirable properties of carbon fibers but are also much more flexible and can be compressed without fracturing. Such excellent mechanical properties make such materials candidates for applications such areas as low-cost and flexible organic electronics, either for their mechanical behavior alone or in conjunction with other desirable properties thereof. However, the potential of using nanotubes as polymer composite reinforcements has, heretofore, not been realized, mainly because of the difficulties in processing and the limitation on electrical properties like low carrier density and mobility of transferring. Several industrial practice challenges must be overcome in order to fully enable such reinforcement by nanotubes.
Some strategies have been proposed to overcome the various barriers to achieving adequate dispersion, including the use of ultrasonication, high-shear mixing, surfactant addition, chemical modification through wrapping the tubes with polymer chains, and various combinations of these. However, to date, only marginal success for nanotube reinforced epoxy composites has been realized, mostly due to the above-mentioned barrier to achievement of sufficient dispersion.
What is needed, therefore, is not only methods for the large-scale manufacture of polymer with carbon nanotubes composites, in which is the polymer composite p-n junction with organic agents and the polymer composite diode incorporates flexible and lightweight p-n junctions, but also to enhance electrical properties like carrier density and mobility.